Soybean (Glycine max L. Merr) has the ability to prevent renal injury due to diazinon intoxicationwhich contains tannin, proanthocyanidin, and isoflavonoid. This study was intended to prove the effect ofsoybean flour administration as nephroprotective agent on diazinon induced rats. This study was conductedat Physiology and Pharmacology Laboratory, Faculty of Medicine Universitas Jember on October-December2017. A total of 25 male wistar rats, aged 12 – 15 months were randomized and divided into 5 groups, normalcontrol group (C1) which was given normal saline solution for 28 days, negative control group (C2) which wasgiven diazinon for 5 days and normal saline solution for 28 days. The treated group was given soybean floursolution with 3 different dosages, 1g/10 ml (C3), 1.5 g/10 ml (C4), and 2g/10 ml (C5) for 28 days, continuedwith diazinon administration of 40 mg/kg for 5 days. Rats euthanasia were done using ether, followed bykidney extraction and its histopathology preparation stained by Hematoxylin Eosin. The observation ofrenal injury severity was assessed by a scoring converted into interval data by using method of successiveinternal (MSI). C1 group had the lowest mean histopathology score 2.427±0.191 whereas the highest meanhistopathology score was on group C2 4.272±0.221. The treated group with the lowest mean histopathologyscore was on group C5 2.875±0.211. There was a significant difference of mean kidney histopathologicalscores between groups (Turkey HSD, p<0.05). This study shows that administration of soybean flour can havea nephroprotective effect from diazinon toxicity which is confirmed by histopathologic examination.